The invention pertains to the field of environmental safety, and more precisely, to the field of radioactive waste treatment of low and intermediate levels containing both combustible components and up to 50% of noncombustible components.
There is a known waste treatment method consisting of solid radioactive waste (SRW) successive transportation in the furnace through the off gas backflow. Waste goes through baking, pyrolysis, incinerating, slag forming, slag and noncombustible SRW melting zones. Further it goes to joint or separate discharging, and cooling to the solid final product for a long-term storage (SU 1810912, 13.08.1990).
Disadvantages of this method are: low speed because of long time of pyrolysis, incinerating, and slag forming and discharging. Also it has a high environmental danger because of intensive radionuclide transfer to gas phase appears under high temperature conditions.
The plasma shaft furnace for radioactive waste treatment is well known. It consists of the restricting bottom-up shaft, equipped by loading unit and off gas pipe in the upper part, and oxidizer (air) supply unit and plasma generators in the bottom part. Also the shafts' bottom part is connected with a horizontal homogenizing chamber, which has in its upper part the vertical plasma reactor (SU 1810912, 13.08.1990).
Disadvantages of this equipment are: the unreliability because of possibility of gas flue blocking by parts of SRW resulting from the short distance from the loading unit, and off-gas speed increasing over the upper part restricting. Also it has the design complexity of a slag discharging unit.
There is known equipment for low and intermediate level radioactive waste treatment which consists of a furnace with a shaft equipped by loading unit and off-gas pipe in the upper part, an oxidizer supply unit in the middle part, and plasma generators in the bottom part. Also the shafts' bottom part is connected with a horizontal homogenizing chamber, which has in its upper part the vertical plasma reactor. There is a melted slag discharging unit in the chambers' bottom part. This unit is a water cooling crystallizer. This equipment also has an off-gas afterburning chamber connected with afterburning product cooling system (cooling heat exchanger) and filter (SU 1810391, 13.08.1990).
A disadvantage of this equipment is unreliability because the melted slag discharging unit design is a poor choice. It has a water cooling crystallizer, and it can be a reason for the low discharging process and final product splitting.
The most similar method to the proposed invention for a technical essence is a method and plant for the treatment of radioactive and toxic waste containing cellulose, polymers, rubber, PVC and non-combustible dirt like a glass and metal, with subsequent incinerating product melting until a solid final product is obtained (RU 2107347, 1998). This method consists in the following.
The waste packaged into the polypropylene containers goes to the plasma shaft furnace heated up to 1400° C. through the loading unit until the shaft is filled. Then the oxidizer (blast air) goes to the shaft through the top and down air supply units. The waste level in the shaft is constant. At the same time, the fuel jet turns on and compressed air goes to the center of shaft. There is a waste burning in the furnace. By gravity, the coke and inorganic part of waste goes to the burning and melting zone located in the homogenizing chamber. The obtained melt exits the furnace through the lower or upper drain hole if needed. The melt flows down through the vertical drain channels into containers. The produced pyrogas exits through the sloped off-gas channel and comes to the afterburning chamber. There is an afterburning of combustible components under the temperature 1000° C., and then gases come to the water cooling system (water evaporator) for cooling from 1000° C. to 300° C. Water is supplied by pneumatic jets. Afterwards, cooled gas goes to the bag filter and then to the heat exchanger for cooling to 250-280° C., and further it goes to the scrubber for acid gas absorption.
Disadvantages of this method are:                the loading system low productivity provided by back-and-forth waste supply system design, and low hermiticity of loading unit;        high amount of fume gases because of fuel burners use and waste burning in the intensive oxidizer supply conditions in the shaft;        the impossibility of liquid radioactive waste treatment by this method;        insufficient degree of off-gas cleaning from radionuclide and aerosols;        the low chemical stability of taken slug in result of free carbon high content in the slug and low homogenization;        plant work unreliability because:                    the gas collecting system design can be a reason of gas flue blocking by SRW parts, and hence, pressure increasing in the furnace;            full shaft height is not used, and there is a radionuclides carry-over possibility;            polypropylene containers use, that can be a reason of the waste moving stoppage in the shaft in result of melting and hanging of polymer package;            low maintainability of the most high-heat elements.                        
The task of the original invention is the elimination of defects described above, with a high safety degree ensuring the provision of a liquid combustible radioactive waste treatment, and an increasing economic effect of radioactive waste treatment.